Induction of hepatic mixed function oxidases by the insecticide, mirex


the effect of mirex (dodecachlorooctahydro-1,3,4-metheno-2H-cyclobuta-[c,d]pentalene) on hepatic cytochrome P-450 and O-demethylase activity has been tested in rats and mice by both injection and feeding studies. Intraperitoneal injection of mirex at a dose rate of 10 mg/kg or higher, increased the hepatic microsomal cytochrome P-450 level in mice. Under the same conditions 25 mg/kg were necessary to elicit the same response in the rat. The O-demethylase activity was also increased. Dietary mirex caused induction of cytochrome P-450 in the rat at all levels tested (1-250 ppm for 14 days). Examination of type I and type II substrate difference spectra indicate that induction at higher levels (100-250 ppm for 14 days) was not only greater but that the cytochrome induced was qualitatively different from that induced at lower levels. Ultrastructural examination of the liver tissue after mirex feeding revealed a proliferation of the smooth endoplasmic reticulum. © 1972.

Publication Title

Environmental Research